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2009

Digital Communications and Networking

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Articles 1 - 26 of 26

Full-Text Articles in Physical Sciences and Mathematics

Structured P2p Technologies For Distributed Command And Control, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins Dec 2009

Structured P2p Technologies For Distributed Command And Control, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins

Faculty Publications

The utility of Peer-to-Peer (P2P) systems extends far beyond traditional file sharing. This paper provides an overview of how P2P systems are capable of providing robust command and control for Distributed Multi-Agent Systems (DMASs). Specifically, this article presents the evolution of P2P architectures to date by discussing supporting technologies and applicability of each generation of P2P systems. It provides a detailed survey of fundamental design approaches found in modern large-scale P2P systems highlighting design considerations for building and deploying scalable P2P applications. The survey includes unstructured P2P systems, content retrieval systems, communications structured P2P systems, flat structured P2P systems and …


Real-World Performance Of Current Proactive Multi-Hop Mesh Protocols, M. Abolhasan, Brett Hagelstein, Jerry Chun-Ping Wang Oct 2009

Real-World Performance Of Current Proactive Multi-Hop Mesh Protocols, M. Abolhasan, Brett Hagelstein, Jerry Chun-Ping Wang

Faculty of Informatics - Papers (Archive)

The proliferation of mesh or ad hoc network protocols has lead to a push for protocol standardisation. While there are a number of both open-source and proprietary mesh routing protocols being developed, there is only a small amount of literature available that shows relative strengths and weaknesses of different protocols. This paper investigates the performance of a number of available routing protocols using a real-world testbed. Three routing protocols - Optimised Link State Routing (OLSR), Better Approach To Mobile Ad hoc Network (B.A.T.M.A.N.) and BABEL - were chosen for this study. Our investigations focus on the multi-hopping performance and the …


Self-Authentication Of Audio Signals By Chirp Coding, Jonathan Blackledge, Eugene Coyle Sep 2009

Self-Authentication Of Audio Signals By Chirp Coding, Jonathan Blackledge, Eugene Coyle

Conference papers

This paper discusses a new approach to ‘watermarking’ digital signals using linear frequency modulated or ‘chirp’ coding. The principles underlying this approach are based on the use of a matched filter to provide a reconstruction of a chirped code that is uniquely robust in the case of signals with very low signal-to-noise ratios. Chirp coding for authenticating data is generic in the sense that it can be used for a range of data types and applications (the authentication of speech and audio signals, for example). The theoretical and computational aspects of the matched filter and the properties of a chirp …


Wireless Networks: Spert: A Stateless Protocol For Energy-Sensitive Real-Time Routing For Wireless Sensor Network, Sohail Jabbar, Abid Ali Minhas, Raja Adeel Akhtar Aug 2009

Wireless Networks: Spert: A Stateless Protocol For Energy-Sensitive Real-Time Routing For Wireless Sensor Network, Sohail Jabbar, Abid Ali Minhas, Raja Adeel Akhtar

International Conference on Information and Communication Technologies

Putting constraints on performance of a system in the temporal domain, some times turns right into wrong and update into outdate. These are the scenarios where apposite value of time inveterate in the reality. But such timing precision not only requires tightly scheduled performance constraints but also requires optimal design and operation of all system components. Any malfunctioning at any relevant aspect may causes a serious disaster and even loss of human lives. Managing and interacting with such real-time system becomes much intricate when the resources are limited as in wireless sensor nodes. A wireless sensor node is typically comprises …


Wireless Networks: Automated Frequency Distribution, Management & Assignment (Afdma) In Ieee 802.16, Khurram Shehzad, A. Ali, F. Rasool, R. M. Hashmi, A. Zubair, R. L. Ali Aug 2009

Wireless Networks: Automated Frequency Distribution, Management & Assignment (Afdma) In Ieee 802.16, Khurram Shehzad, A. Ali, F. Rasool, R. M. Hashmi, A. Zubair, R. L. Ali

International Conference on Information and Communication Technologies

Frequency is amongst the most exclusive and most costly resources in wireless communication networks, especially, while considering the demands of broadband wireless access (BWA). In BWA, the management of frequency distribution and its effective utilization is of utmost importance. This research explores possible ways to ensure the most effective allocation of bandwidth resources and their best possible utilization on need basis. The model for static frequency allocation has been optimized and the dynamic frequency management has been calculated while dividing the users in different user classes on the basis of their needs and requirements. The effect of ping-pong handovers has …


Networks - Ii: Formal Modeling Of Trust In Semantic Grid Registry, Saba Mahmood, Saman Iftikhar, Hafiz Farooq Ahmad, Farah Mahmood Aug 2009

Networks - Ii: Formal Modeling Of Trust In Semantic Grid Registry, Saba Mahmood, Saman Iftikhar, Hafiz Farooq Ahmad, Farah Mahmood

International Conference on Information and Communication Technologies

In this paper we have analyzed and developed a formal specification of a trust model in semantic grid registry. This paper formalizes the basic requirements of a trust model in case of semantic grid registry. We have described the flow of operations of our system through links and processes in the system architecture. The system is formally modeled in pi-calculus. Finally we transformed the specification to pi- ADL and generated code using Archware tool. We have already developed a semantic grid registry.


Application Of Ict - I: Using Point-To-Point 1550nm Laser For Outdoor Mobility, Roshan A. Shaikh, Abdul Basit Aug 2009

Application Of Ict - I: Using Point-To-Point 1550nm Laser For Outdoor Mobility, Roshan A. Shaikh, Abdul Basit

International Conference on Information and Communication Technologies

Significant implementation challenges exist in wireless backbone connectivity. Typical optical wireless communication topologies are evaluated. A fresh approach using 1550nm Wavelength laser to design protocol and topology for point-to-point outdoor connectivity is carried out. Matlab simulation results support the 1550nm laser as a good choice for outdoor connectivity for optical wireless communication. New design and topology for an optical wireless communication system is suggested with special consideration of security and recommendation for the optimal use of such a technology is suggested.


Networks - I: Networks-On-Chip: Challenges, Trends And Mechanisms For Enhancements, Omer Tayan Aug 2009

Networks - I: Networks-On-Chip: Challenges, Trends And Mechanisms For Enhancements, Omer Tayan

International Conference on Information and Communication Technologies

The rate of increase of silicon capacity in integrated circuits (IC) will enable system integration of several billion transistors to reside on a single chip in the near future. Future system-on-chip (SoC) systems must therefore integrate up to several hundreds of cores within a single chip, and SoC designs will employ on-chip communication networks (NoCs) as a result. This paper discusses the problems with many current SoC systems, surveys the challenges and trends facing future SoC designs and proposes a mechanism for enhancing NoC strategies of the future by enhancing memory management and utilization techniques within an NoC.


Networks - I: A Comparative Analysis Of Dccp Variants (Ccid2, Ccid3), Tcp And Udp For Mpeg4 Video Applications, Muhammad Ajmal Azad, Rashid Mahmood, Tahir Mehmood Aug 2009

Networks - I: A Comparative Analysis Of Dccp Variants (Ccid2, Ccid3), Tcp And Udp For Mpeg4 Video Applications, Muhammad Ajmal Azad, Rashid Mahmood, Tahir Mehmood

International Conference on Information and Communication Technologies

New emerging technologies like Multimedia applications require timely delivery of information as compared to reliability. The most widely used protocols over transport layer are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). Both of these have some drawbacks while using in real time applications. TCP increases delay in transfer of data but achieving reliable transfer of data while UDP does not provide any acknowledgment, hence it overcomes the problem of delay but lacking congestion control mechanism. To provide congestion control over transport layer using UDP, Datagram Congestion Control Protocol (DCCP) has been designed to provide timely delivery of data …


Artificial Intelligence – I: A Two-Step Approach For Improving Efficiency Of Feedforward Multilayer Perceptrons Network, Shoukat Ullah, Zakia Hussain Aug 2009

Artificial Intelligence – I: A Two-Step Approach For Improving Efficiency Of Feedforward Multilayer Perceptrons Network, Shoukat Ullah, Zakia Hussain

International Conference on Information and Communication Technologies

An artificial neural network has got greater importance in the field of data mining. Although it may have complex structure, long training time, and uneasily understandable representation of results, neural network has high accuracy and is preferable in data mining. This research paper is aimed to improve efficiency and to provide accurate results on the basis of same behaviour data. To achieve these objectives, an algorithm is proposed that uses two data mining techniques, that is, attribute selection method and cluster analysis. The algorithm works by applying attribute selection method to eliminate irrelevant attributes, so that input dimensionality is reduced …


Using Timed-Release Cryptography To Mitigate The Preservation Risk Of Embargo Periods, Rabia Haq, Michael L. Nelson Jun 2009

Using Timed-Release Cryptography To Mitigate The Preservation Risk Of Embargo Periods, Rabia Haq, Michael L. Nelson

Computer Science Presentations

PDF of a powerpoint presentation from the 2009 ACM/IEEE Joint Conference on Digital Libraries, Austin, Texas, June 15-19, 2009. Also available on Slideshare.


Store And Forward Routing For Sparse Pico-Satellite Sensor Networks With Data-Mules, Trevor Joseph Koritza Jun 2009

Store And Forward Routing For Sparse Pico-Satellite Sensor Networks With Data-Mules, Trevor Joseph Koritza

Master's Theses

Satellites are playing an increasingly important role in collecting scientific information, providing communication services, and revolutionizing navigation. Until recently satellites were large and very expensive, creating a high barrier to entry that only large corporations and government agencies could overcome. In the past few years the CubeSat project at California Polytechnic University in San Luis Obispo (Cal Poly) has worked to refine the design and launching of small, lightweight, and less expensive satellites called pico-satellites, opening space up to a wider audience. Now that Cal Poly has the launch logistics and hardware under control, a new problem has arisen. These …


Adding Escience Assets To The Data Web, Herbert H. Van De Sompel, Carl Lagoze, Michael L. Nelson, Simeon Warner, Robert Sanderson, Pete Johnston Apr 2009

Adding Escience Assets To The Data Web, Herbert H. Van De Sompel, Carl Lagoze, Michael L. Nelson, Simeon Warner, Robert Sanderson, Pete Johnston

Computer Science Faculty Publications

Aggregations of Web resources are increasingly important in scholarship as it adopts new methods that are data-centric, collaborative, and networked-based. The same notion of aggregations of resources is common to the mashed-up, socially networked information environment of Web 2.0. We present a mechanism to identify and describe aggregations of Web resources that has resulted from the Open Archives Initiative - Object Reuse and Exchange (OAI-ORE) project. The OAI-ORE specifications are based on the principles of the Architecture of the World Wide Web, the Semantic Web, and the Linked Data effort. Therefore, their incorporation into the cyberinfrastructure that supports eScholarship will …


A Taxonomy For And Analysis Of Anonymous Communications Networks, Douglas J. Kelly Mar 2009

A Taxonomy For And Analysis Of Anonymous Communications Networks, Douglas J. Kelly

Theses and Dissertations

Any entity operating in cyberspace is susceptible to debilitating attacks. With cyber attacks intended to gather intelligence and disrupt communications rapidly replacing the threat of conventional and nuclear attacks, a new age of warfare is at hand. In 2003, the United States acknowledged that the speed and anonymity of cyber attacks makes distinguishing among the actions of terrorists, criminals, and nation states difficult. Even President Obama’s Cybersecurity Chief-elect recognizes the challenge of increasingly sophisticated cyber attacks. Now through April 2009, the White House is reviewing federal cyber initiatives to protect US citizen privacy rights. Indeed, the rising quantity and ubiquity …


Using Covert Means To Establish Cybercraft Command And Control, Bradley D. Sevy Mar 2009

Using Covert Means To Establish Cybercraft Command And Control, Bradley D. Sevy

Theses and Dissertations

With the increase in speed and availability of computers, our nation's computer and information systems are being attacked with increased sophistication. The Air Force Research Laboratory (AFRL) Information Directorate (RI) is researching a next generation network defense architecture, called Cybercraft, that provides automated and trusted cyber defense capabilities for AF network assets. This research we consider the issues to protect or obfuscate command and control aspects of Cybercraft. In particular, we present a methodology to hide aspects of Cybercraft platform initialization in context to formation of hierarchical, peer-to-peer groups that collectively form the Cybercraft network. Because malicious code networks (known …


Low Probability Of Intercept Waveforms Via Intersymbol Dither Performance Under Multipath Conditions, Jonathan K. Keen Mar 2009

Low Probability Of Intercept Waveforms Via Intersymbol Dither Performance Under Multipath Conditions, Jonathan K. Keen

Theses and Dissertations

This thesis examines the effects of multipath interference on Low Probability of Intercept (LPI) waveforms generated using intersymbol dither. LPI waveforms are designed to be difficult for non-cooperative receivers to detect and manipulate, and have many uses in secure communications applications. In prior research, such a waveform was designed using a dither algorithm to vary the time between the transmission of data symbols in a communication system. This work showed that such a method can be used to frustrate attempts to use non-cooperative receiver algorithms to recover the data. This thesis expands on prior work by examining the effects of …


The Modular Clock Algorithm For Blind Rendezvous, Nicholas C. Theis Mar 2009

The Modular Clock Algorithm For Blind Rendezvous, Nicholas C. Theis

Theses and Dissertations

This thesis examines the problem in initializing communications whereby cognitive radios need to find common spectrum with other cognitive radios, a process known as frequency rendezvous. It examines the rendezvous problem as it exists in a dynamic spectrum access cognitive network. Specifically, it addresses the problem of rendezvous in an infrastructureless environment. A new algorithm, the modular clock algorithm, is developed and analyzed as a solution for the simple rendezvous environment model, coupled with a modified version for environment models with less information. The thesis includes a taxonomy of commonly used environment models, and analysis of previous efforts to solve …


Numerical Analysis For Relevant Features In Intrusion Detection (Narfid), Jose Andres Gonzalez Mar 2009

Numerical Analysis For Relevant Features In Intrusion Detection (Narfid), Jose Andres Gonzalez

Theses and Dissertations

Identification of cyber attacks and network services is a robust field of study in the machine learning community. Less effort has been focused on understanding the domain space of real network data in identifying important features for cyber attack and network service classification. Motivations for such work allow for anomaly detection systems with less requirements on data “sniffed” off the network, extraction of features from the traffic, reduced learning time of algorithms, and ideally increased classification performance of anomalous behavior. This thesis evaluates the usefulness of a good feature subset for the general classification task of identifying cyber attacks and …


Adaptive Control Of Woofer-Tweeter Adaptive Optics, Jimmie J. Perez Feb 2009

Adaptive Control Of Woofer-Tweeter Adaptive Optics, Jimmie J. Perez

Theses and Dissertations

Adaptive optics applies advanced sensing and control to improve the ability of optical systems to collect images through a turbulent atmosphere. The results of this research effort demonstrate that the combination of two recent approaches improves the performance of adaptive optics in directed energy and laser communication scenarios. The first approach is adaptive control, which offers improved performance over fixed-gain controllers in the presence of rapidly changing turbulence. The second approach incorporated into the study is a dual-mirror system. The two mirrors are a high-bandwidth, low-actuator-stroke (tweeter) mirror and a low-bandwidth, large actuator-stroke (woofer) mirror. The woofer-tweeter combination allows for …


Automated Virtual Machine Introspection For Host-Based Intrusion Detection, Brett A. Pagel Feb 2009

Automated Virtual Machine Introspection For Host-Based Intrusion Detection, Brett A. Pagel

Theses and Dissertations

This thesis examines techniques to automate configuration of an intrusion detection system utilizing hardware-assisted virtualization. These techniques are used to detect the version of a running guest operating system, automatically configure version-specific operating system information needed by the introspection library, and to locate and monitor important operating system data structures. This research simplifies introspection library configuration and is a step toward operating system independent introspection. An operating system detection algorithm and Windows virtual machine system service dispatch table monitor are implemented using the Xen hypervisor and a modified version of the XenAccess library. All detection and monitoring is implemented from …


An Fpga-Based System For Tracking Digital Information Transmitted Via Peer-To-Peer Protocols, Karl R. Schrader Feb 2009

An Fpga-Based System For Tracking Digital Information Transmitted Via Peer-To-Peer Protocols, Karl R. Schrader

Theses and Dissertations

This thesis addresses the problem of identifying and tracking digital information that is shared using peer-to-peer file transfer and Voice over IP (VoIP) protocols. The goal of the research is to develop a system for detecting and tracking the illicit dissemination of sensitive government information using file sharing applications within a target network, and tracking terrorist cells or criminal organizations that are covertly communicating using VoIP applications. A digital forensic tool is developed using an FPGA-based embedded software application. The tool is designed to process file transfers using the BitTorrent peer-to-peer protocol and VoIP phone calls made using the Session …


Multicast Encryption Infrastructure For Security In Sensor Networks, Richard R. Brooks, Brijesh Pillai, Matthew Pirretti, Michele C. Weigle Jan 2009

Multicast Encryption Infrastructure For Security In Sensor Networks, Richard R. Brooks, Brijesh Pillai, Matthew Pirretti, Michele C. Weigle

Computer Science Faculty Publications

Designing secure sensor networks is difficult. We propose an approach that uses multicast communications and requires fewer encryptions than pairwise communications. The network is partitioned into multicast regions; each region is managed by a sensor node chosen to act as a keyserver. The keyservers solicit nodes in their neighborhood to join the local multicast tree. The keyserver generates a binary tree of keys to maintain communication within the multicast region using a shared key. Our approach supports a distributed key agreement protocol that identifies the compromised keys and supports membership changes with minimum system overhead. We evaluate the overhead of …


A Covert Encryption Method For Applications In Electronic Data Interchange, Jonathan Blackledge, Dmitry Dubovitskiy Jan 2009

A Covert Encryption Method For Applications In Electronic Data Interchange, Jonathan Blackledge, Dmitry Dubovitskiy

Articles

A principal weakness of all encryption systems is that the output data can be ‘seen’ to be encrypted. In other words, encrypted data provides a ‘flag’ on the potential value of the information that has been encrypted. In this paper, we provide a new approach to ‘hiding’ encrypted data in a digital image.

In conventional (symmetric) encryption, the plaintext is usually represented as a binary stream and encrypted using an XOR type operation with a binary cipher. The algorithm used is ideally designed to: (i) generate a maximum entropy cipher so that there is no bias with regard to any …


Hierarchical Routing In Manets Using Simple Clustering, Adam Carnine Jan 2009

Hierarchical Routing In Manets Using Simple Clustering, Adam Carnine

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis presents both a review of current MANET routing protocols and a new MANET routing algorithm. The routing protocols reviewed include representative samples from the three primary forms of routing found in MANETS: proactive routing, reactive routing and hybrid routing. Secure algorithms are given special treatment in the review. In addition several protocol enhancements are discussed.

The proposed routing protocol is designed to support networks of a medium size, containing over 200 nodes but less than 3,000 nodes. The design is intentionally simple to allow ease of implementation in comparison with other MANET protocols that provide similar functionality.


Supporting Protocols For Structuring And Intelligent Information Dissemination In Vehicular Ad Hoc Networks, Filip Cuckov Jan 2009

Supporting Protocols For Structuring And Intelligent Information Dissemination In Vehicular Ad Hoc Networks, Filip Cuckov

Electrical & Computer Engineering Theses & Dissertations

The goal of this dissertation is the presentation of supporting protocols for structuring and intelligent data dissemination in vehicular ad hoc networks (VANETs). The protocols are intended to first introduce a structure in VANETs, and thus promote the spatial reuse of network resources. Segmenting a flat VANET in multiple cluster structures allows for more efficient use of the available bandwidth, which can effectively increase the capacity of the network. The cluster structures can also improve the scalability of the underlying communication protocols. The structuring and maintenance of the network introduces additional overhead. The aim is to provide a mechanism for …


High-Performance Broadcast And Multicast Protocols For Multi-Radio Multi-Channel Wireless Mesh Networks, Jun Wang Jan 2009

High-Performance Broadcast And Multicast Protocols For Multi-Radio Multi-Channel Wireless Mesh Networks, Jun Wang

Electrical & Computer Engineering Theses & Dissertations

Recently, wireless mesh networks (WMNs) have attracted much attention. A vast amount of unicast, multicast and broadcast protocols has been developed for WMNs or mobile ad hoc networks (MANETs). First of all, broadcast and multicast in wireless networks are fundamentally different from the way in which wired networks function due to the well-known wireless broadcast/multicast advantage. Moreover, most broadcast and multicast protocols in wireless networks assume a single-radio single-channel and single-rate network model, or a generalized physical model, which does not take into account the impact of interference. This dissertation focuses on high-performance broadcast and multicast protocols designed for multi-radio …